Table 2.

Insulin secretion by single beta cells in response to a 1 h incubation to blocker drugs in different extracellular glucose concentrations.

Treatment	Glucose (mmol/L)	Percentage of plaque-forming cells	Plaque area (μm2)
Control	5.6	23.9 ± 0.9	1,291 ± 258
	15.6	62.2 ± 2.0	2,200 ± 248
Nifedipine (5 µM)	5.6	21.4 ± 6.8	994 ± 156+
	15.6	23.6 ± 4.1*	917 ± 117*
Mibefradil (1 µM)	5.6	17.3 ± 3.7+	1,088 ± 63
	15.6	24.8 ± 5.4*	1,055 ± 123*
Ni CI2 (50 µM)	5.6	24.3 ± 9.5	1,250 ± 284
	15.6	42.6 ± 3.1*	1,516 ± 114*
TTA-A2 (50 µM)	5.6	13.3 ± 0.9+	883 ± 19+
	15.6	41.1 ± 0.2*	1,289 ± 268*
Nifedipine + TTA-A2	5.6	7.8 ± 0.7+	497 ± 95+
	15.6	17.4 ± 4.8*	581 ± 56*

Symbols, (+) denotes significant differences with respect to control cells at 5.6 mM glucose, (*) denotes significant differences with respect to control cells at 15.6 mM glucose Dunnet test (analysis of variance).